Feature/cleanup

[aerorahul]

This PR:

• adds a .gitignore file
• adds a README.md file
• adds a VERSION file that provides version number of the library
• cleans up CMakeLists.txt

The CMakeLists.txt clean-up includes:

• adds a version to the project, along with languages
• uses standard build types and checks for supported compilers.
• removal of globbing of source files
• using a CMake defined variables where appropriate
• splits compiler flags into common, debug, release
• uses add_compile_definitions where appropriate instead of compile_flags
• removes POSITION_INDEPENDENT_CODE. Libraries are built as STATIC. If SHARED is desired, this feature is automatically added by cmake.
• formatting using cmake-format